The present invention relates to a brake pressure control valve for vehicular brake systems comprising a housing having a threaded plug at its outlet; a stepped piston having its larger-diameter portion guided in a bore of the threaded plug and its smaller-diameter portion guided in a bore formed in the housing, the stepped piston including an axial channel and a valve seat at the entrance of the axial channel, the stepped piston being slidable from a predetermined inactive position in the closing direction against the force of a valve spring bearing against a fixed stop; and a spring-loaded closure member whose inactive position is defined by a support formed in the housing.
In a known brake pressure control valve of the aforementioned type, such as disclosed in German Patent DE-OS No. 2,938,140, following the thread for the threaded plug, the housing includes a first bore of larger diameter. Adjacent thereto via a step is a bore of smaller diameter in which the smaller-diameter portion of the stepped piston is guided. An end portion constructed as a threaded pipe includes an enlarged bore wherein the closure member is held. The valve spring is supported on the step of the housing and urges a flange on the stepped piston against the end face of the threaded plug. When screwing in the threaded plug, both the preload of the valve spring and the closure travel are changed in this construction. Therefore, a considerable deviation of the control valve's operational values has to be put up with.